RU216040U1 - VACUUM CONTACTOR - Google Patents

Abstract

The utility model relates to switching devices with a single rest position, with an electromagnetic control system and can be used in the field of electrical engineering, in contactors and starters. The technical result consists in increasing the power of the electromagnetic drive. The vacuum contactor contains movable and fixed contacts, the electromagnetic drive containing two coils contains a normally closed contact connected to the windings of two coils made of round wire, while the electromagnetic drive coils contain starting and additional windings connected to each other. 1 ill.

Description

The utility model relates to switching devices with a single rest position, with an electromagnetic control system. The utility model can be used in the field of electrical engineering, in contactors and starters.

The closest technical solution (prototype) is a vacuum electromagnetic contactor (RU 164777, publ. 09/20/2016), containing a housing made of electrically insulating material with a partition and an L-shaped lever having arms of various lengths, at least one vacuum arc chute with movable and fixed contacts, an electromagnetic drive, at least one electromagnet, containing a flat armature, a yoke, a coil and a core, a compression spring designed to open the contacts, equipped with a means for adjusting the load value, in which the body partition is located between the vacuum arc chute and electromagnetic drive, the axes of the coil and the core are located perpendicular to the bulkhead of the housing, the long arm of the L-shaped lever is kinematically connected to the movable contact by means of the rod head, and in the short arm a longitudinal groove is made in which a flat armature is fixed, and when the electromagnet is de-energized, it is short The first arm is located at an acute angle to the housing partition in such a way that the part of the flat anchor remote from the axis of the L-shaped lever contacts the surface of the housing partition or the stop fixed on it, and when the flat anchor contacts the core, between the long arm of the L-shaped lever and the head stem has a gap. The disadvantage of the known solution is the relatively low power of the electromagnetic drive.

The task to be solved by the claimed utility model is to increase the power of the electromagnetic drive.

This problem is solved by the fact that the vacuum contactor includes movable and fixed contacts, an electromagnetic drive containing two coils, a normally closed contact connected to the windings of two coils made of round wire, while the electromagnetic drive coils contain starting and additional windings connected between yourself.

The technical result provided by the above set of features is an increase in the power of the electromagnetic drive.

The utility model can be used in the field of electrical engineering in contactors and starters.

The term "contactor" (contact switching device) means that the device is designed to turn on and off in one or more electrical circuits.

The term "contact" means conductive parts designed to establish the continuity of the circuit when they come into contact and, as a result of their movement relative to each other during operation, open or close the circuit. The fixed contact of the switching device remains fixed in the "on" position. The movable contact moves relative to the fixed contact until it comes into contact with the contact piece of the fixed contact in the “on” position.

The term "main contact" means a contact included in the main circuit of a contact switching device, designed to carry in the closed position the current of the main circuit.

The term "opening" of the contacts means operation, as a result of which the contacts of the device are transferred from the closed position to the open position, while the fixed contact of the switching device remains stationary. The movable contact moves relative to the fixed contact, in the open position a gap is formed between the movable and fixed contact.

The term "closing" means operation, as a result of which the device is transferred from the open position to the closed position.

The term “make contact” means a contact that is closed when the main contacts of the contact switching device are closed and open when the main contacts are open.

The term "normally closed" (break contact) means a contact that is open when the main contacts of the contact switching device are closed and closed when the main contacts are open.

The term "operating" (contact switching apparatus) means control by applying the energy accumulated in the mechanism itself until the completion of the operation and sufficient to bring it to the end under the given conditions.

The term "closed position" (contact switching device) means a position in which the intended continuity of the main circuit of the device is ensured.

The expression "the contactor contains an electromagnetic drive" means that the force necessary to close the main contacts of the switching devices is provided by an electromagnet, the components of the electromagnetic drive include all parts that are connected to the components of the magnet.

The term "moving part of the magnet" means the part of the magnet that changes its position relative to the fixed part of the magnet, in the closed and open position of the main contacts.

The term "coil" means a set of turns of enameled wire on a frame. The coil of the electromagnetic drive according to this utility model means a coil that is part of an electromagnet, the operation of which leads to the closure of the main contacts.

The term "starting winding" means a set of turns of enameled wire that create an electromagnetic field during the passage of the starting current.

The term "additional winding" (working winding) means a set of enameled wire turns that create an electromagnetic field during the passage of the rated operating current.

The term (expression) "round wire" means that at least one wire section is round.

The utility model is illustrated by a figure, which shows a bottom view of the device.

The contactor contains an electromagnetic drive equipped with two coils (each of the two coils consists of a starting and additional winding) 1, a lever 2, a traverse with contacts 3, an additional contact block 4.

The electromagnetic drive of the contactor, the coils of which contain starting and additional windings connected to each other, contains a normally closed contact connected to the windings of two coils made of round wire, thereby increasing the power of the electromagnetic drive.

The electromagnetic drive is equipped with two coils, the windings of these coils are interconnected. In this case, the connection of the windings of two coils to each other ensures the joint operation of the two coils as a whole, as one powerful electromagnetic drive. Thus, connecting the windings of two coils together increases the power of the electric drive by increasing the electromagnetic induction of the coils.

Each coil of the electromagnetic drive is equipped with a starting and additional windings. In the open position of the normally closed contact, power is supplied to both the starting winding and the additional winding of the electromagnetic drive, thus, the number of turns of the coil becomes larger, due to the addition of turns of the additional coil.

To find the magnetic induction modulus of a coil consisting of one layer, you can use formula (1). The magnetic induction of the coil is

where N is the number of coil turns;

l is the length of the coil;

n is the number of turns per unit length;

I - current in the coil;

μ is the magnetic permeability of the medium inside the coil;

μ ₀ - magnetic constant.

From formula (1) it can be seen that, other things being equal, the magnetic induction of the coil is directly proportional to the number of turns of the coil.

From formula (1) it can be seen that due to the opening of the normally closed contact, the additional winding is connected to the starting one, the number of turns becomes larger and the power of the electromagnetic drive increases.

In the closed position of the normally closed contact, power is supplied only to the starting winding of the electromagnetic drive.

The calculation of the inductance of a single-row coil is carried out according to the formula (2):

where L is the inductance;

μ ₀ - free space permeability = 4π × 10 ^-7 H / m;

μ _r - relative permeability of the core material;

N is the number of turns;

S is the cross-sectional area of the coil;

l is the length of the coil.

For round wire

S = π (D/2)², (Formula 3),

where S is the cross-sectional area of the wire;

π - 3.14;

D is the diameter of the wire.

It can be seen from the formula that the larger the diameter of the wire, the greater the current strength and the greater the magnetic induction. Therefore, using a wire with a larger diameter compared to a smaller diameter helps create a stronger magnetic field (ceteris paribus).

A normally closed contact is connected to the windings of two coils. In the closed position of the normally closed contact, power is supplied only to the starting winding of the electromagnetic drive. The diameter of the starting winding wire is larger than the diameter of the additional winding wire. The operation of only the starting winding of the coils provides a powerful electromagnetic field during the start of the contactor, providing more power for the electromagnetic drive. Due to the fact that the diameter of the wire of the starting winding is larger than the diameter of the wire of the additional winding, and the larger the diameter of the conductor, the greater the magnetic field (the calculation is given by formula 3), a greater powerful electromagnetic field is provided during the start of the contactor and the power of the electromagnetic drive as a whole increases.

For example, the diameter of the starting winding wire may be in the range of 0.18-1 mm, and the diameter of the additional winding may be in the range of 0.1-0.7 mm. Thus, the starting winding, made with a wire of a larger diameter than the diameter of the wire of the additional winding, provides a powerful electromagnetic drive at start-up and protects the contactor contacts from overheating, however, long-term operation of only the starting winding causes overheating, and connecting an additional winding protects the coil winding from overheating and increases the number of turns, thus, the operation of the contactor becomes safe and the power of the electromagnetic drive increases by increasing the number of turns. The additional and starting windings of each coil are interconnected.

A normally closed contact is connected to the windings of two coils. The additional winding of the solenoid drive coil is controlled and connected to a normally closed contact. This allows you to apply voltage (start up) to the additional windings of the coils of the electromagnetic drive when the contact is opened, thus ensuring the joint operation of the starting and additional windings. Consequently, the total number of turns of the coil winding increases, it can be seen from formula (1) that this increases the power of the electromagnetic drive.

The electromagnetic drive contains a normally closed contact (closed contact at rest), connected to the starting and additional windings of two coils, when opened, power is supplied to the additional windings of the electromagnetic drive. Due to this, the NC contact supplies voltage to the additional winding, and it is connected to the starting winding, thus ensuring the joint operation of the starting and additional windings. Consequently, the total number of turns of the coil winding increases, it can be seen from formula (1) that this increases the power of the electromagnetic drive.

The contactor is equipped with a lever 2 that controls the opening of a normally closed contact that controls the inclusion of additional windings. This allows you to open the normally closed contact and apply power to the additional windings. Due to the fact that the vacuum contactor is equipped with a lever to open the normally closed contact, the contact opens and voltage is applied to the additional winding, and it is connected to the starting winding, thus ensuring the joint operation of the starting and additional windings. Consequently, the total number of turns of the coil winding increases, it can be seen from formula (1) that this increases the power of the electromagnetic drive.

Lever 2 is used as the part that controls the opening of the normally closed contact, the design of the vacuum contactor can have one or two levers that control the opening of the normally closed contact.

The moving part of the electromagnetic actuator drives the lever. This allows the normally closed contact to be opened after the contactor has started and to supply power to the auxiliary windings. This design allows the starting winding to fulfill its role during the start-up of the contactor, providing a powerful force during start-up, and then start an additional winding designed for long-term operation and providing a powerful electromagnetic field to provide the power of the electromagnetic drive, since to hold the contacts in the closed position a different electromagnetic drive force (produced by the coil windings) is required than at start-up. The starting winding, when working together with an additional winding, does not overheat, since the voltage passes through both the starting and additional windings.

Coil windings (additional and starting) are made of round wire. The winding of the coils from a round wire leads to an increase in the power of the electromagnetic drive when compared with a square wire.

The area S of a square wire is a² = 0.045216, hence a = 0.21264 is the side of the square of the square wire.

The area S of a round wire is πR² = 0.045216, hence R=0.12, D=2R=0.24 is the diameter of the round wire.

Thus, for equal values of the area of the circular and square sections D of the circle> a square.

Let's make a calculation for several more values of the conductor cross sections:

The area S of a square wire is a² \u003d 0.080384 hence a \u003d 0.28352 - the side of the square of the square wire.

The area S of the round wire πR² = 0.080384 hence R=0.16, D=2R=0.32 is the diameter of the round wire.

Thus, for equal values of the area of the circular and square sections D of the circle> a square.

Thus, for equal values of the area of the round and square sections of the wire, there is always D circle> a square.

The coil is a hollow cylinder.

The formula for calculating the cross-sectional area of a coil is:

S \u003d π × (Dn ² - Din ² ) / 4, where

Dn - outer diameter of the coil;

Dv is the inner diameter of the coil.

S \u003d π × (Dn ² - Din ² ) / 4

Cross-sectional area of round wire coil:

S \u003d π × ((nD + Dv) ² -Dv ² ) / 4 \u003d π × (n ² *D ² + 2nD × Dv + Dv ² -Dv ² ) / 4 \u003d π × (n ² ×D ² + 2nD ×Dv)/4 = π×D(n ² ×D+2n×Dv)/ 4,

Cross Sectional Area of Square Wire Coil:

S \u003d π × ((na + Dv) ² -Dv ² ) / 4 \u003d π × (n ² × a ² + 2na × Dv + Dv ² -Dv ² ) / 4 \u003d π × (n ² ×a ² + 2na ×Dv)/4 = π×a(n ² ×a+2n×Dv)/4,

where Dn is the outer diameter of the coil;

Dv is the inner diameter of the coil.

n is the number of turns in one row - let's take this value the same for all cases;

D-diameter of the cross-section of a round wire (width of one turn);

a - the side of the square of the square wire (width of one turn).

At equal Dв, Dн for a square wire section = n × a + Dв, where

n is the number of turns in one row - let's take this value the same for all cases

a is the side of the square, then

Dn for round wire section = n×D+Dv

From the above formulas, it can be seen that for D> a, other things being equal,

π×D(n ² ×D+2n×Dв)/ 4>π×a(n ² ×a+2n×Dв)/ 4,

and, therefore, the cross-sectional area of the round wire coil is greater than the cross-sectional area of the square wire coil.

When Dv is equal for square and round sections, Dn for a square wire section is n×a, where

n is the number of turns in one row - let's take this value the same for all cases;

a-side of the square (winding width);

Dn for a circular cross section of the wire is n × D;

where n is the number of turns in one row - let's take this value the same for all cases;

D-diameter of circular section (winding width).

We calculate the inductance of the coil for a single-row coil:

,

,

where L is the inductance;

μ ₀ - free space permeability = 4π × 10 ^-7 H / m;

μ _r - relative permeability of the core material;

N is the number of turns;

S is the cross-sectional area of the coil;

l is the length of the coil.

Calculate the inductance L for a single-row coil.

The values, μ ₀ , μ _r , N will be the same both for a coil with a round wire section and for a coil where the wire section is square, therefore, their product will be the same in both cases.

Thus, the variable part of the formula includes either a (the side of the square) or D (the diameter of the circle). We will transform the formula according to mathematical laws to obtain a visual result.

Inductance L of a coil made of round wire:

L = μ ₀ ×μ _r ×N ² ×π×D×(n ² ×D+2n×Dv)/4D=μ ₀ ×μ _r ×N ² ×π×(n ² ×D+2n×Dv)/ four.

Inductance L of a coil made of square wire:

L = μ ₀ ×μ _r ×N ² ×π×a×(n ² ×a+2n×Dv)/4a=μ ₀ ×μr×N ² ×π×(n ² ×a+2n×Dv)/4 .

Therefore, if D> a, then the inductance L of the coil made of round wire will be greater than the inductance of the coil made of square wire. It can be seen from the formula that, other things being equal, since the diameter D of the circular section of the wire is greater than the side a of the square section of the wire, then the inductance L of the coil of the circular section of the wire is greater than the inductance L of the coil of the square section of the wire.

Let us calculate the magnetic flux for a coil of round and square wire section under given conditions.

F \u003d L × I,

where Ф - magnetic flux;

L - inductance;

I - current strength.

When the inductance L of the coil of a circular section of the wire is greater than the inductance L of the coil of the square section of the wire, the magnetic flux Ф of the coil of the circular section of the wire is greater than the magnetic flux Ф of the coil of the square section of the wire.

Thus, with the same material consumption (equal to the conductor area) and other things being equal, the power of the magnet will be greater if the winding is made of a round wire.

Due to the implementation of the windings of the coils of the electromagnetic drive of the proposed switching device with a round wire, the power of the electromagnetic drive increases, the pressing force of the movable contact to the fixed contact improves, and the contact improves.

The device works as follows.

After the voltage is applied to both coils 1, only the starting winding is switched on when the contact is closed (moving contact of the auxiliary contact block 4). Only the starting winding works, starting to attract the movable part of the electromagnetic drive, fixed on the lever 2. The movable part of the electromagnetic drive is attracted to the core and drives the lever 2, the lever 2 rotates around the axis and presses the traverse 3 of the additional contact block 4, opens the normally closed contact placed in the block of additional contacts 4. The block of additional contacts 4 consists of a spring-loaded part-traverse 3, made of dielectric material, for fastening and moving moving contacts, fixed contacts fixed in the case of the block of additional contacts, while the fixed contacts are equipped with clamps for connecting current-carrying wires. When pressing on the traverse 3, it moves the moving contacts, while the normally open contacts are closed, i.e. the moving contact is in contact with the fixed contact, and the normally closed contacts open. Auxiliary contact block 4 provides one normally open and one normally closed contact, or, depending on the configuration, two normally open and two normally closed contacts. The contactor can be equipped with one or two blocks of additional contacts 4. Traverse 3 with movable contacts (block of additional contacts) starts to move, as a result of which the normally closed contact that controls the start of voltage to the additional windings, to which the coil windings are connected, opens and the additional winding is deshunted connected in series to the starting winding. The windings of the coils are interconnected. The outputs of the coils of the electromagnetic drive of the electromagnetic drive are brought to the terminal block, as a rule, the contactor has two switching coils, the outputs of both coils are brought to the terminal block, which has two windings: starting and additional. The additional winding is shunted by a normally closed contact of the auxiliary contact block. When current passes through the turns of the control coils, an electromagnetic field is created, and the movable part of the electromagnetic drive is attracted to the stationary part of the electromagnetic drive.

Claims (1)

Vacuum contactor, including moving and fixed contacts, electromagnetic drive containing two coils, characterized in that the contactor contains a normally closed contact, the coils of the electromagnetic drive contain starting and additional windings connected to each other, while the contactor is equipped with a lever that controls the opening of the normally closed contact , which controls the inclusion of additional windings, and the movable part of the electromagnetic drive drives the lever.

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